so is the Kalachakra Tantra considered Pure Vision? I find it really interesting that there seems to be a fixed date in the future. Just seems such a weird juxtaposition to all the impermanence, etc. found in Buddhism.

Also didn't know that the Gadhimai Festival was the second largest ritual sacrifice of animals.

The different sūtras in accord with the emptiness
taught by the Sugata are definitive in meaning;
One can understand that all of those Dharmas in
which a sentient being, individual, or person are taught are provisional in meaning.

it was taught by the Buddha. I guess that answered my question. Thanks Malcolm.

If you are a Vajrayāna practitioner, then yes you think it was taught by the Buddha. The tantra itself was not actually written down at first, only much later, and there are a couple of versions a long one which we do not have, and the short one which we do have.

The different sūtras in accord with the emptiness
taught by the Sugata are definitive in meaning;
One can understand that all of those Dharmas in
which a sentient being, individual, or person are taught are provisional in meaning.

Kalachakra Tradition in Tibet
The Dro lineage was established in Tibet by a Kashmiri disciple of Nalandapa named Pandita Somanatha, who traveled to Tibet in 1027 (or 1064 AD, depending on the calendar used), and his translator Droton Sherab Drak Lotsawa, from which it takes its name. This Dro lineage has been sustained primarily by the Jonang tradition. The Ra lineage was brought to Tibet by another Kashmiri disciple of Nadapada named Samantashri, and translated by Ra Choerab Lotsawa (or Ra Dorje Drakpa). The Ra lineage became particularly important in the Sakya tradition of Tibetan Buddhism, where it was held by such prominent masters as Sakya Pandita (1182-1251), Drogon Chogyal Pagpa (1235-1280), Budon Rinchendrup (1290-1364), and Dolpopa Sherab Gyaltsen (1292-1361) who recieved a Sakya education at an early age but was one of the great Jonang masters. The latter two, both of whom also held the Dro lineage, are particularly well known expositors of the Kalachakra in Tibet, the practice of which is said to have greatly informed Dolpopa’s exposition of the zhentong or shentong view upheld by the Jonang. A strong emphasis on Kalachakra practice, along with exposition of the zhentong view, are the principle distinguishing characteristics of the Jonang tradition that Dolpopa upheld.
The teaching of the Kalachakra was further advanced by the great Jonang scholar Taranatha (1575-1634). In the 17th century, the Gelug-led government of Tibet outlawed the Jonang tradition for political reasons, closing down or forcibly converting most of its monasteries in Central Tibet. The writings of Dolpopa, Taranatha, and other prominent scholars were banned. Ironically, it was also at this time that the Gelug lineage absorbed much of its Kalachakra tradition from the Jonang.
Today Kalachakra is practiced by all five Tibetan traditions of Buddhism, although it appears most prominently in the Jonang and Gelug lineages. It remains central to the Jonang tradition which exists in Eastern Tibet. Khenpo Kunga Sherab Rinpoche is one contemporary Jonangpa master of the Kalachakra.
Buton had considerable influence on the later development of the Gelug and Sakya traditions of Kalachakra, and Dolpopa on the development of the Jonang tradition on which the Kagyu and Nyingma draw. The Kagyu and Nyingma rely heavily on the extensive, Jonang-influenced Kalachakra commentaries of Ju Mipham and Jamgon Kongtrul the Great, both of whom took a strong interest in the tradition.